Multi-stage Switching Fabric Fault Location Algorithm

The explosive development of Internet and the data service on it which is likely getting faster every day poses a higher performance request to the switching and routing system. As the request for both the quantity and the quality of the date service is rapidly growing, the switching fabrics, which is the key component of the switching and routing systems, do not only have to be competent for the high-speed and reliable switching job , but also have to fit the huge switching volume and even acclimatize themselves to update the size regularly . With the limits of the structure,the num of chip's pin and the complexity of IC implementing , the single-stage structure is not able to accomplish the task of building up a scalable high speed large switching system ,which brings the multi-stage solution to the front stage . The multi-staged switching structure has a great many advantage such as the scalability, distributed modularized structure etc. and is a very effective solution for problems of the growing service quantity and switching speed. The clos network architecture, which is a very typical type of the multistage fabrics, has been an even getting hot spot of the research and implementing of large high speed switching system.As a large non-blocking solution in circuit switching invented back to the 50s of last century, clos switching network's still reliable scheme of building high-performance packet switching device. There have been a lot of achievements in the improvement and route organizing algorithm, some of which are already implemented in commercial producing. Otherwise the research in the defect tolerance and reliability of clos switching network hasn't received that much attention.This article has developed a scheme for detecting defects in the clos switching network which is judging the cross-point switches for good or not with the exterior data link. Based on the scheme, the article also introduced two specific detecting algorithm: one is used in the initialized testing before products leave factory, which is aimed to make sure the whole fabric is 100% ok; the other is used to get the defect location when a certain data path is reported to have defects on it during the service. Both of the algorithms are proved to perform well in the clos switching networks. Besides, this article provided some advice to reduce the operation complexity of the practical implementing of the algorithms.